In a network including a plurality of nodes and many links for connecting the nodes, a route control system determines an optimum route for a flow in the network in accordance with constraint conditions such as an accessibility condition, a traffic capacity condition, and a route length (the number of hops) condition, in response to a requested flow that has been made by a source terminal in order to transmit data to a destination terminal. The route control system operates in a network management system (NMS) which is connected to each node so as to control the each node. The route control system shifts the status of each node on the route from a sleep state corresponding to a power saving mode to a wake state corresponding to a normal enabled status, and sets (allocates) the data flow in (to) the specified route.
In order to determine the optimum route for a requested flow that meet the constraint conditions, it is proposed to determine a route that minimizes the sum of “costs”. The “cost” is assumed to be expended, in execution of traffic processing, at each link on the route. The determination is made in accordance with an objective function (MIN {Σi, Σj, Li,j}, wherein Li,j indicates a link cost value of a link from a node i to a node j). Japanese Translation of PCT International Application Publication No. 2005-518717 and Japanese Laid-open Patent Publication No. 2003-338832 disclose related techniques. The cost may be any physical amounts expended in traffic processing for each data flow by each node and each link on the route, for example. Specific examples of the physical amounts include a transmission power and a reception power of each node, a band of each link, and a connection charge for use of each link.